Method of copolymerizing ethylene with butadiene



Patented June 3, 1952 UNITED STATES METHOD QBOLYMERIZINGETHYIIENE W-IIH. BUTDENE Bernard S. Friedman, Chicago, Ill., assignor-to`- Sinclair Refining Company, New York, N. Y.,. a corporation of Maine NoDrawing, Application. lMarch.77,1950, serialz-No. 148:2.73

'1 Clai'm. (Cl. 2611-6809' I have discovered that ethylene will copolymer- Y prisingly attractive yields of higher molecular l weight straight-chain dioleln copolymer products. For example, I have found that reacting ethylene, vat aV space velocity of. about75 volumes measured asgas at S. T. P..per volume` of catalyst per hour, with butadiene, at a space -velocity vof about 150, in thev presenceA of coconut charcoal vimpregnated with. cobalt: oxide atabout 195 F. and 200 p. s. i. g. results in they formation of reaction products containinghexadiene, octadiene and 'decadiene in good. yield.

In accordance. with my invention. ethylenejs reacted with butadiene to formthe higher mo.- ,lecular weightv Vstraight-chain diolle'n copolymers. Ihave found that reactionof -only ethylene under similar conditions. willl result. in. the formation of straight c hain. olefin polymers, such as butene, heXene, octene, et`c. Propylene, for instance, yis I highly Y resistant. toany polymerization at all. OnV the other. hand, I havefound that thereacton. of butadiene alone tends to .the formation of. cyclic polymers s uchas vinylcyclohexene and any straight. chai'npolymerzation products incidentally formedare in very :voor yield- '.lhe amounts of- ,ethylene-- .and butadiene reacted maybe varied considerably.` Howevenan excessive proportion of either tends to poor yields and is generally wasteful. I have foundthat space velocities in the range approximating-25 to 4 00'r volumes of each reactantpenvolunrie-ofV catalyst penhour results in the. f`c rinatio nY of? attractive amounts ofl copolymerV reaction prod-f ucts. In particular, space velocities of abouty50' to 300 fori-.each are. advantageously employed; In addition; 'I have found it desirable to remove any oxygen, sulfurA or other compoundsin the ethylene which might poison the catalyst. For

instance; thewethylene may bezpassedfpver acjtivated nickelA priortosreactien--to eliminate.` these contaminants..

The copolymerization` reaction is effected at temperatures Yin the Vrangeapproximating.1657 toe 575 andai; l pressures .betweenr -about'ft0bi-to 11000 p. s.i. g. Ipreferthermal reactionenvirom- .ments of about.. 20.0 .to .3.009 F. at#pressures'lof about 0-te 300 pj. s. ing;

Although my` invention `is not predicate'dupon any particular theory. .it .is .my belief that-.the reaction ,proceeds as .ai stepwise additinnfilie molecules of ethylene to-thebutadienelmole'cule.

Y For' instance,. as follows:

and so forth. It is also Vinteresting to note that more severe reaction conditions within the scope EXAMPLE I Ethylene and butadiene were introduced into a stainless steel reactor tube containing 250 cc.

of lactivated coconut charcoal impregnated with The reactiorrisvcarried'out inthe presence. of

asupported cobalt oxide catalyst.. In particular, 'If have foundcobalt oxide deposited on a woodr charcoal oran activated coconutcharcoal support' tombe highly advantageous as acatalyst..

cobaltoxide and heated by doughnut heaters surrounding the tube. The ethylene gas feed was rstpassed through activated nickel in order toremove catalyst poisoning agents such as oxygen and sulfur compounds. The ethylene was passed into the reactor tube at a space velocity of 72 volumes per volume of catalyst per hour andmthe butadiene through a separate line at a Spacevelocity of 153 v./v./hr. The reaction was -carried out at a temperature of about 194 F.

and at a pressure of 200 p. s. i. g. A total of 45 grams,` of ethylene and grams of butadiene were reacted. 240 grams of eiuent products were taken off from the reaction zone and passed through a vapor-liquid separator where 21 grams of heavier, liquid components were removed from the gas stream. These liquid products were fractionated and the resulting cuts analyzed for refractive index, gravity and hydrogen value, as follows:

Cut No. 1

Average boiling range, F 150-158 Weight per cent of charge to still 13.4 Refractive index, N420 1.4132 Gravity, D420 0.694 Hydrogen value (catalytic hydrogenation) 490 Cut No. 2

Average boiling range, F 264 Weight per cent of charge to still 9.6 Refractive index, N420 1.4379 Gravity, D420 Y 0.751 Hydrogen value (catalytic hydrogenation) 502 Cut No. 3

Average boiling range, F 340 Weight per cent of charge to still 8.7

Refractive index, N420 1.4383

Gravity, D420 0.783 Hydrogen value (catalytic hydrogenation) 376 EXAMPLE II Ethylene and butadiene were introduced into a reaction system similar to that of Example I at space velocities of 230 v./v./hr. and 90 v./v./hr., lrespectively. The reaction was carried out at a temperature of about 400 F.y at a pressure of 400 p. s. i. g. A total of 144 grams of ethylene and '112 grams of butadiene were reacted. 6.3% of ,ethylene and 52.6% of butadiene-by weight were converted. 294 grams of eiuent products were taken oi from the reaction zone and passed through a vapor-liquid separator, where 83.0 grams of heavier, liquid components were removed from the gas stream. These liquid productsv were fractionated and the resulting cuts drogen value, as follows:

Cut No. 1

Average boiling range, F. 248 Weight per cent of charge to still 11.5

Refractive index, N132 1.4279

Gravity, D420 0.729 Hydrogen value (catalytic hydrogenation) 380 Cut No 2 Average boiling range, F. 269 Weight per cent of charge to still 10.5 Refractive index, ND2D 1.4598 Gravity, D420 0.794 Hydrogen value (catalytic hydrogenation) 430 Cut No. 3'

Average boiling range, F 343 Weight per cent of charge to still 9.8

Refractive index, No2 1.4481

Gravity, D420 0.775 Hydrogen value (catalytic hydrogenation) 300 The gas stream'from Which these liquid products were removed was then passed through a Dry Ice-acetone trap where the condensible portion, 47.0 grams, was removed. The non-condensible gases, 164.0 grams, had an average molecularrweight of 31.1.

Thus distillation of the eiluent liquid products from these exemplary runs show the formation of higher molecular weight straight-chain'diolen copolymer products. For instance, the liquid effluent of Example I was distilled into a Ce-rich fraction (above, Cut No. 1) containing at least hexadiene, apparently the 1,4- isomer; a Ca-rich fraction (Cut No. 2) containing principally octadiene, apparently the 1,6- and 2,6-isomers; and a C10-rich fraction (Cut No. 3) composed mostly of decadiene. Accordingly, the butadiene has apparently condensed with one, two and three molecules of ethylene, respectively, to form the higher copolymers.

In Example II, distillation showed that octadene (Cut No. 2) anddecadiene (Cut No. 3) fractions were formed, although the hexadiene fraction` apparently was not present. These difierences probably derive in large measure from the fact that the run comprising Example II was conducted at higher temperatures and pressures.

Comparison of the distillation cuts from each example with literature data for pure compounds clearly illustrate the nature of my results:

Cut No. 1 Literature Data for:

EX. I Ex. Il S-Hexene 1,4-COH10 1,5-C6H10 1,5-(351114 B. P. F 150-158 248 152. 6 14S 139 244.5 1120.'. 1. 4132 1. 4279 1. 3942 1.4162 1. 4040 1.4265 42 0. 694 0. 729 0. 6816 0. 0996 0. 6916 0. 7314 Hz Va1ue-- 490 380 302 620 620 460 Cut No. 2 Literature Data for:

EX. I EX. II 1,7-CsH14 1,6-CBH14 2,6-CAH14 Cut No. 3 lliterature Data for:

Ex.I EX.II 2,8-C10H1s 3,7-C10H1s 1,3-010H1i 114-0101311 B. P., F- 340 343 334 332 333 11341' n, Vahle. 373 300 33s 36s 303 V33s 1 claim: 10 REFERENCES CITED The method 0f formmg hquld higher molecu' The following references are of record in the lar weight straight-chain diolefln copolymers me if this patent. having from 6 to 10 carbon atoms which comprises the step of reacting ethylene with butaf UNITED STATES PATENTS diene in the presence of cobalt oxide-charcoal l5 Nurnber Name Date catalyst at a temperature in the range approxi- 2,200,429 Perrin et al. May 14, 1940 mating 165 to 575 F. and at a. pressure between 2,332,276 Stahly Oct. 19, 1943 about 100 to 1000 p. s. i. g. at a reaction space 2,381,198 Bailey et al. -;-.f.-.. Aug. 7, 1945 velocity in the range of about 25 to 400 volumes o! each of the ud reactants per volume of cat- 20 alyst per hour.

BERNARD S. FRIEDMAN. 

